This invention relates to compositions and methods for conditioning fabrics during home laundering operations. More specifically, this invention relates to compositions and methods that are employed during the laundry rinse cycle in order to improve the tactile properties of laundered fabrics. The compositions produce minimal fabric staining and can be prepared in highly stable form.
Rinse-cycle fabric conditioning is widely used. Such rinse-cycle fabric conditioning imparts to laundered fabrics a texture or handle that is smooth, pliable and fluffy to the touch. Moreover, conditioning of fabrics in the deep rinse can also impart to laundered fabrics a reduced tendency to pick up and/or retain static charge. The former property of conditioned fabrics is generally called fabric "softness" and the latter property is generally called fabric "static control".
Widely used rinse-added fabric conditioning compositions are aqueous suspensions or emulsions comprising major amounts of water, lesser amounts of fabric conditioning compounds, and minor amounts of optional ingredients such as perfumes, dyes, preservatives and stabilizers. These aqueous compositions can be conveniently added to the rinse bath during the rinsing cycle of automatic laundry operations.
Many compounds have been disclosed as having the capacity to condition fabrics and, in particular, to soften fabrics. Typically representative of such compounds are those cation-active compounds appearing in column 2 of U.S. Pat. No. 3,756,950 issued Sept. 4, 1973 to Gluck and entitled "Fabric Softening Compositions". Moreover, certain diamine compounds have been disclosed as through-the-wash fabric softeners in British Pat. No. 1,356,827 published June 19, 1974; issued to Henkel & Cie GmbH. Further U.S. Pat. No. 3,879,300 issued Apr. 22, 1975 to Renold and entitled "Diamine Containing Softener Compositions" and U.S. Pat. No. 3,154,489 issued Oct. 27, 1964 to Du Brow et al and entitled "Surface Active Compositions" disclose, respectively, diamine and ethoxylated diamines in certain fabric conditioning compositions.
Although these and many other fabric conditioning compounds are known, there is a continuing need for aqueous rinse-added compositions and methods which not only soften fabrics but which furthermore provide highly effective fabric static control. This need is especially apparent given the widespread use of synthetic fibers in textile fabrics and the tendency of these fibers to pick up and retain static charge.
Moreover, although a variety of aqueous liquid fabric conditioning compositions have been disclosed in the art, many of these liquid compositions do not have optimum physical stability over wide temperature ranges. Stability problems generally arise because of the solubility characteristics of the ingredients commonly used in such aqueous liquid fabric conditioning compositions. The ability of many compounds to provide rinse-added fabric conditioning is related to the rate of deposition of the compounds onto fabrics from the aqueous rinse baths. Consequently, it is usually desirable to employ fabric conditioning compounds which are relatively insoluble in water. This water-insolubility can provide equilibrium conditions highly favorable for deposition of the fabric conditioning compounds onto the fabrics from aqueous rinse baths.
However, this very water-insolubility of rinse-added fabric conditioning compounds makes for difficulty in incorporating them into physically stable and economical aqueous liquid rinse-added products. Often aqueous liquid fabric conditioning compositions require specialized mixing techniques using relatively expensive emulsifiers and/or solvents for optimized stability and performance. Even with these techniques, however, the stability of many prior art aqueous fabric conditioning compositions is not wholly satisfactory, especially when such compositions are subjected to extreme temperature variations. There is then a continuing need for stable liquid fabric conditioning compositions which provide exceptional fabric softening and static control.
Accordingly, it is an object of the present invention to provide compositions and methods for conditioning fabrics during the rinse cycle of laundering operations.
It is a further object of the invention herein to provide fabric conditioning compositions and methods that not only provide a desirable degree of fabric softening but that also provide exceptionally effective fabric static control.
It is a further object of the invention herein to provide aqueous fabric conditioning compositions of exceptional physical stability.
These and other objectives are realized by means of the present invention. Aqueous liquid compositions of the invention herein can be made in highly stable form. Remarkably, they even can be prepared as clear products and yet, when added to aqueous rinse baths, the clear products provide the highly favorable water/fabric equilibrium necessary for optimum fabric conditioning performance. Moreover, the clear compositions can be opacified for aesthetic appeal without any substantial loss in stability or performance. Alternatively, the compositions herein can be prepared as stable emulsions and/or suspensions.